希尔排序

/**
 * 排序算法之希尔排序
 */
 #include <iostream>
 #include <vector>
 using namespace std;

 void sortXiEr(vector<int>& vec, int len) {
    int i, j;
    int increment = len;
    while (increment > 1) {
        increment = increment / 3 + 1;
        for (i = increment; i < len; ++i) {
            int key = vec[i];
            j = i;
            while (j >= increment && key < vec[j - increment]) {
                vec[j] = vec[j - increment];
                j -= increment;
            }
            vec[j] = key;
        }
    }
 }

 int main() {
    vector<int> vec = {2,1,3,5,4};
    int len = vec.size();
    sortXiEr(vec, len);
    for (int i = 0; i < len; ++i) {
        cout << vec[i] << endl;
    }
    return 0;
 }